Messages in this thread | | | From | Cengiz Can <> | Date | Thu, 30 Jul 2020 11:59:10 +0300 | Subject | Re: [PATCH] staging: atomisp: move null check to earlier point |
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On July 30, 2020 11:48:06 Dan Carpenter <dan.carpenter@oracle.com> wrote:
> On Wed, Jul 29, 2020 at 06:13:44PM +0300, Andy Shevchenko wrote: >> On Wed, Jul 29, 2020 at 5:00 PM Cengiz Can <cengiz@kernel.wtf> wrote: >>> >>> `find_gmin_subdev` function that returns a pointer to `struct >>> gmin_subdev` can return NULL. >>> >>> In `gmin_v2p8_ctrl` there's a call to this function but the possibility >>> of a NULL was not checked before its being dereferenced. ie: >>> >>> ``` >>> /* Acquired here --------v */ >>> struct gmin_subdev *gs = find_gmin_subdev(subdev); >>> int ret; >>> int value; >>> >>> /* v------Dereferenced here */ >>> if (gs->v2p8_gpio >= 0) { >>> pr_info("atomisp_gmin_platform: 2.8v power on GPIO %d\n", >>> gs->v2p8_gpio); >>> ret = gpio_request(gs->v2p8_gpio, "camera_v2p8"); >>> if (!ret) >>> ret = gpio_direction_output(gs->v2p8_gpio, 0); >>> if (ret) >>> pr_err("V2P8 GPIO initialization failed\n"); >>> } >>> ``` >>> >>> I have moved the NULL check before deref point. >> >> "Move the NULL check..." >> See Submitting Patches documentation how to avoid "This patch", "I", "we", etc.
Noted. Sorry. I'm not a native English speaker.
>> > > I always feel like this is a pointless requirement. We're turning into > bureaucracts. > >> >>> diff --git a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c >>> b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c >>> index 0df46a1af5f0..8e9c5016f299 100644 >>> --- a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c >>> +++ b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c >>> @@ -871,6 +871,11 @@ static int gmin_v2p8_ctrl(struct v4l2_subdev *subdev, >>> int on) >>> int ret; >>> int value; >>> >>> + if (!gs) { >>> + pr_err("Unable to find gmin subdevice\n"); >> >>> + return -EINVAL; >> >> And here is a change of semantics... > > Yeah. The change of semantics should be documented in the commit > message, but it's actually correct. I discussed this with Mauro earlier > but my bug reporting script didn't CC a mailing list and I didn't > catch it. Mauro suggested: > > 53 > Yet, it could make sense to have something like: > 54 > > 55 > if (WARN_ON(!gs)) > 56 > return -ENODEV; > 57 > > 58 > at the beginning of the functions that call find_gmin_subdev().
I will be updating v2 according to this.
> > regards, > dan carpenter
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